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<head><meta charset="utf-8"><title>meeting 2021-02-02 · wg-traits · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/index.html">wg-traits</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html">meeting 2021-02-02</a></h3>

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<a name="224935407"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224935407" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224935407">(Feb 02 2021 at 20:57)</a>:</h4>
<p>Hi <span class="user-group-mention" data-user-group-id="692">@WG-traits</span></p>



<a name="224935417"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224935417" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224935417">(Feb 02 2021 at 20:57)</a>:</h4>
<p>meeting in 3ish minutes</p>



<a name="224935526"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224935526" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224935526">(Feb 02 2021 at 20:58)</a>:</h4>
<p>Today we should maybe talk about current state of GATs?</p>



<a name="224935889"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224935889" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224935889">(Feb 02 2021 at 21:01)</a>:</h4>
<p>wave -- running a bit late</p>



<a name="224936069"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224936069" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224936069">(Feb 02 2021 at 21:02)</a>:</h4>
<p>We could. Do you mean GATs in rustc or in chalk?</p>



<a name="224936221"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224936221" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224936221">(Feb 02 2021 at 21:03)</a>:</h4>
<p>rustc</p>



<a name="224936273"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224936273" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224936273">(Feb 02 2021 at 21:03)</a>:</h4>
<p>Current state, current issues, what stabilization of GATs with lifetimes might look like</p>



<a name="224936388"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224936388" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224936388">(Feb 02 2021 at 21:04)</a>:</h4>
<p>/me scrolling a bit through <a href="https://github.com/rust-lang/rust/issues/44265">rust#44265</a></p>



<a name="224936410"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224936410" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224936410">(Feb 02 2021 at 21:04)</a>:</h4>
<p>OK, here now</p>



<a name="224936421"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224936421" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224936421">(Feb 02 2021 at 21:05)</a>:</h4>
<p>Before that, did anyone have any announcements?</p>



<a name="224936424"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224936424" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224936424">(Feb 02 2021 at 21:05)</a>:</h4>
<p>so I didn't have time to do much background reading</p>



<a name="224936583"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224936583" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224936583">(Feb 02 2021 at 21:06)</a>:</h4>
<p><a href="https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3AF-generic_associated_types">Link</a> for GAT issues</p>



<a name="224936634"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224936634" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224936634">(Feb 02 2021 at 21:06)</a>:</h4>
<p>But also <a href="https://github.com/rust-lang/rust/issues/79554">#79554</a></p>



<a name="224936854"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224936854" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224936854">(Feb 02 2021 at 21:08)</a>:</h4>
<p>There are 28 issues open for GATs</p>



<a name="224936892"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224936892" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224936892">(Feb 02 2021 at 21:08)</a>:</h4>
<p>hmmm</p>



<a name="224936897"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224936897" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224936897">(Feb 02 2021 at 21:08)</a>:</h4>
<p>But <a href="https://github.com/rust-lang/rust/issues/79554">#79554</a> will close 7 of those</p>



<a name="224936962"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224936962" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224936962">(Feb 02 2021 at 21:09)</a>:</h4>
<p>maybe a triage of the GAT issues is a good idea</p>



<a name="224936981"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224936981" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224936981">(Feb 02 2021 at 21:09)</a>:</h4>
<p>I was thinking though: we <em>are</em> planning on trying to stabilize GATs with lifetimes before GATs with types/consts?</p>



<a name="224937007"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937007" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937007">(Feb 02 2021 at 21:09)</a>:</h4>
<p>In that case, it might be a good idea to split the <code>generic_associated_types</code> feature into two</p>



<a name="224937015"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937015" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937015">(Feb 02 2021 at 21:09)</a>:</h4>
<p>I'm debating about it</p>



<a name="224937017"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937017" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937017">(Feb 02 2021 at 21:09)</a>:</h4>
<p>only lifetimes vs everything</p>



<a name="224937026"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937026" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937026">(Feb 02 2021 at 21:09)</a>:</h4>
<p>that probably makes sense</p>



<a name="224937097"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937097" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937097">(Feb 02 2021 at 21:10)</a>:</h4>
<p>Const sounds hardest, not sure about types vs lifetimes</p>



<a name="224937109"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937109" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937109">(Feb 02 2021 at 21:10)</a>:</h4>
<p>i guess the question is what gets easier because of excluding types</p>



<a name="224937140"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937140" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937140">(Feb 02 2021 at 21:10)</a>:</h4>
<p><span class="user-mention silent" data-user-id="116009">nikomatsakis</span> <a href="#narrow/stream/144729-wg-traits/topic/meeting.202021-02-02/near/224936962">said</a>:</p>
<blockquote>
<p>maybe a triage of the GAT issues is a good idea</p>
</blockquote>
<p>how do people feel about this as a concept?</p>



<a name="224937154"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937154" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937154">(Feb 02 2021 at 21:11)</a>:</h4>
<p>that is, I think we could do that now</p>



<a name="224937163"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937163" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937163">(Feb 02 2021 at 21:11)</a>:</h4>
<p>Well, so, the problem with non-lifetimes is things like <code>rustc_resolve::late::lifetimes</code> can't handle anything but late-bound lifetimes</p>



<a name="224937174"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937174" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937174">(Feb 02 2021 at 21:11)</a>:</h4>
<p><span class="user-mention silent" data-user-id="116009">nikomatsakis</span> <a href="#narrow/stream/144729-wg-traits/topic/meeting.202021-02-02/near/224937154">said</a>:</p>
<blockquote>
<p>that is, I think we could do that now</p>
</blockquote>
<p>yeah!</p>



<a name="224937198"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937198" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937198">(Feb 02 2021 at 21:11)</a>:</h4>
<p>Let me make a hackmd</p>



<a name="224937209"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937209" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937209">(Feb 02 2021 at 21:11)</a>:</h4>
<p><a href="https://hackmd.io/uxoObhSxSRijNmfmGkId0g">https://hackmd.io/uxoObhSxSRijNmfmGkId0g</a></p>



<a name="224937222"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937222" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937222">(Feb 02 2021 at 21:12)</a>:</h4>
<p>heh, I had one, but it was empty</p>



<a name="224937224"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937224" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937224">(Feb 02 2021 at 21:12)</a>:</h4>
<p>we'll use yours!</p>



<a name="224937282"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937282" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937282">(Feb 02 2021 at 21:12)</a>:</h4>
<p>let's go oldest to newest?</p>



<a name="224937289"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937289" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937289">(Feb 02 2021 at 21:12)</a>:</h4>
<p>I don't know why, just because</p>



<a name="224937306"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937306" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937306">(Feb 02 2021 at 21:12)</a>:</h4>
<h1>Allow generic associate types in trait paths <a href="https://github.com/rust-lang/rust/issues/67510">#67510</a></h1>



<a name="224937337"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937337" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937337">(Feb 02 2021 at 21:12)</a>:</h4>
<p>well, I guess we could start with the tracking issue</p>



<a name="224937379"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937379" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937379">(Feb 02 2021 at 21:13)</a>:</h4>
<h1><span aria-label="science" class="emoji emoji-1f52c" role="img" title="science">:science:</span> Tracking issue for generic associated types (GAT) <a href="https://github.com/rust-lang/rust/issues/44265">#44265</a></h1>



<a name="224937386"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937386" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937386">(Feb 02 2021 at 21:13)</a>:</h4>
<p>but there doesn't seem to be much there?</p>



<a name="224937393"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937393" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937393">(Feb 02 2021 at 21:13)</a>:</h4>
<p>nope</p>



<a name="224937400"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937400" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937400">(Feb 02 2021 at 21:13)</a>:</h4>
<p>I don't think anything relevant</p>



<a name="224937412"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937412" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937412">(Feb 02 2021 at 21:13)</a>:</h4>
<p>5 open blocking bugs?</p>



<a name="224937439"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937439" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937439">(Feb 02 2021 at 21:13)</a>:</h4>
<p>ah those are all labeled</p>



<a name="224937444"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937444" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937444">(Feb 02 2021 at 21:13)</a>:</h4>
<p>I think we should circle back to that list</p>



<a name="224937448"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937448" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937448">(Feb 02 2021 at 21:13)</a>:</h4>
<p>since we'll encounter them as we go</p>



<a name="224937451"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937451" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937451">(Feb 02 2021 at 21:13)</a>:</h4>
<p>exactly</p>



<a name="224937495"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937495" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937495">(Feb 02 2021 at 21:14)</a>:</h4>
<p><span class="user-mention silent" data-user-id="116009">nikomatsakis</span> <a href="#narrow/stream/144729-wg-traits/topic/meeting.202021-02-02/near/224937306">said</a>:</p>
<blockquote>
<h1>Allow generic associate types in trait paths <a href="https://github.com/rust-lang/rust/issues/67510">#67510</a></h1>
</blockquote>



<a name="224937526"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937526" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937526">(Feb 02 2021 at 21:14)</a>:</h4>
<p>So</p>



<a name="224937533"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937533" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937533">(Feb 02 2021 at 21:14)</a>:</h4>
<p>pretty simple</p>



<a name="224937556"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937556" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937556">(Feb 02 2021 at 21:14)</a>:</h4>
<p>And <a href="https://github.com/rust-lang/rust/issues/79554">#79554</a> directly addresses</p>



<a name="224937581"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937581" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937581">(Feb 02 2021 at 21:14)</a>:</h4>
<p>there is a bit of a design question</p>



<a name="224937591"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937591" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937591">(Feb 02 2021 at 21:15)</a>:</h4>
<p>do you <em>have</em> to give a name</p>



<a name="224937603"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937603" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937603">(Feb 02 2021 at 21:15)</a>:</h4>
<p>what if you do <code>dyn Foo&lt;Y&lt;'a&gt; = u32&gt;</code></p>



<a name="224937629"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937629" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937629">(Feb 02 2021 at 21:15)</a>:</h4>
<p>I forget if we answered this in the RFC</p>



<a name="224937672"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937672" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937672">(Feb 02 2021 at 21:15)</a>:</h4>
<p>I don't remember</p>



<a name="224937680"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937680" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937680">(Feb 02 2021 at 21:15)</a>:</h4>
<p>lurking a bit here and I don't want to distract, but meanwhile I read your discussion and try to follow up, is there a place that condenses what's the current status of things? what's missing? what are the main difficulties and all that?</p>



<a name="224937732"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937732" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937732">(Feb 02 2021 at 21:16)</a>:</h4>
<p>that's kind of what we're trying to figure out, <span class="user-mention" data-user-id="116266">@Santiago Pastorino</span></p>



<a name="224937748"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937748" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937748">(Feb 02 2021 at 21:16)</a>:</h4>
<p>by traiging issues</p>



<a name="224937758"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937758" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937758">(Feb 02 2021 at 21:16)</a>:</h4>
<p>the "basic state" is that things "kind of mostly work"</p>



<a name="224937803"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937803" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937803">(Feb 02 2021 at 21:16)</a>:</h4>
<p>I guess the question is</p>
<div class="codehilite"><pre><span></span><code>fn f(x: Box&lt;dyn X&lt;Y&lt;&#39;a&gt;=&amp;&#39;a ()&gt;&gt;) {}
</code></pre></div>
<p>or</p>
<div class="codehilite"><pre><span></span><code>fn f(x: Box&lt;dyn for&lt;&#39;a&gt; X&lt;Y&lt;&#39;a&gt;=&amp;&#39;a ()&gt;&gt;) {}
</code></pre></div>



<a name="224937822"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937822" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937822">(Feb 02 2021 at 21:16)</a>:</h4>
<p>I'd call <a href="https://github.com/rust-lang/rust/issues/67510">#67510</a> blocking</p>



<a name="224937848"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937848" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937848">(Feb 02 2021 at 21:17)</a>:</h4>
<p>we should probably clarify our categories</p>



<a name="224937858"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937858" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937858">(Feb 02 2021 at 21:17)</a>:</h4>
<p>but to start I would say we are looking at "blocking / non-blocking'</p>



<a name="224937867"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937867" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937867">(Feb 02 2021 at 21:17)</a>:</h4>
<p>and maybe we'll add more notes as we go?</p>



<a name="224937916"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937916" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937916">(Feb 02 2021 at 21:17)</a>:</h4>
<p>Works for me</p>



<a name="224937938"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224937938" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224937938">(Feb 02 2021 at 21:17)</a>:</h4>
<h1>GAT ICE: impl item and trait item have different parameter counts <a href="https://github.com/rust-lang/rust/issues/68648">#68648</a></h1>



<a name="224938007"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938007" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938007">(Feb 02 2021 at 21:18)</a>:</h4>
<p>looks like it has a pending fix</p>



<a name="224938037"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938037" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938037">(Feb 02 2021 at 21:18)</a>:</h4>
<p>Same PR</p>



<a name="224938064"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938064" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938064">(Feb 02 2021 at 21:18)</a>:</h4>
<p>blocking</p>



<a name="224938067"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938067" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938067">(Feb 02 2021 at 21:18)</a>:</h4>
<p>There's like 3 or 4 issues that have roughly the same example</p>



<a name="224938103"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938103" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938103">(Feb 02 2021 at 21:19)</a>:</h4>
<h1>GAT ICE: place local already assigned to <a href="https://github.com/rust-lang/rust/issues/68649">#68649</a></h1>



<a name="224938133"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938133" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938133">(Feb 02 2021 at 21:19)</a>:</h4>
<p>same thing</p>



<a name="224938136"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938136" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938136">(Feb 02 2021 at 21:19)</a>:</h4>
<p>yep</p>



<a name="224938139"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938139" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938139">(Feb 02 2021 at 21:19)</a>:</h4>
<p>ok</p>



<a name="224938159"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938159" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938159">(Feb 02 2021 at 21:19)</a>:</h4>
<p>same with 68650 and 68652</p>



<a name="224938291"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938291" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938291">(Feb 02 2021 at 21:20)</a>:</h4>
<h1>Yield reference in generator with GAT <a href="https://github.com/rust-lang/rust/issues/69268">#69268</a></h1>



<a name="224938302"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938302" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938302">(Feb 02 2021 at 21:20)</a>:</h4>
<p>just a feature request</p>



<a name="224938309"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938309" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938309">(Feb 02 2021 at 21:20)</a>:</h4>
<p>re. generators</p>



<a name="224938316"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938316" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938316">(Feb 02 2021 at 21:20)</a>:</h4>
<p>non-blocking</p>



<a name="224938367"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938367" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938367">(Feb 02 2021 at 21:21)</a>:</h4>
<p>I also probably wouldn't even feel comfortable thinking about this until close to stabilization</p>



<a name="224938376"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938376" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938376">(Feb 02 2021 at 21:21)</a>:</h4>
<p>(at the earliest)</p>



<a name="224938386"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938386" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938386">(Feb 02 2021 at 21:21)</a>:</h4>
<p>definitely not blocking</p>



<a name="224938394"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938394" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938394">(Feb 02 2021 at 21:21)</a>:</h4>
<p>doesn't even seem like a "GAT" bug</p>



<a name="224938443"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938443" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938443">(Feb 02 2021 at 21:21)</a>:</h4>
<h1>GAT: the type <code>[type error]</code> has an unknown layout <a href="https://github.com/rust-lang/rust/issues/70303">#70303</a></h1>



<a name="224938522"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938522" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938522">(Feb 02 2021 at 21:22)</a>:</h4>
<p>blocking</p>



<a name="224938526"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938526" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938526">(Feb 02 2021 at 21:22)</a>:</h4>
<p>same as 70304</p>



<a name="224938554"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938554" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938554">(Feb 02 2021 at 21:22)</a>:</h4>
<p>both are similiar</p>



<a name="224938640"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938640" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938640">(Feb 02 2021 at 21:23)</a>:</h4>
<p>yeah</p>



<a name="224938750"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938750" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938750">(Feb 02 2021 at 21:24)</a>:</h4>
<p>blocking but basically just kind of "misc bug"</p>



<a name="224938767"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938767" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938767">(Feb 02 2021 at 21:24)</a>:</h4>
<p>no known fix yet</p>



<a name="224938819"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938819" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938819">(Feb 02 2021 at 21:24)</a>:</h4>
<p><a href="https://github.com/rust-lang/rust/issues/71176">#71176</a> is also fixed by <a href="https://github.com/rust-lang/rust/issues/79554">#79554</a> from the looks of it</p>



<a name="224938915"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938915" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938915">(Feb 02 2021 at 21:25)</a>:</h4>
<p>yes, but not labeled as such in PR, will discuss that in review</p>



<a name="224938944"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938944" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938944">(Feb 02 2021 at 21:25)</a>:</h4>
<h1>GAT: open drop from non-ADT <code>[type error]</code> <a href="https://github.com/rust-lang/rust/issues/70304">#70304</a></h1>



<a name="224938952"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938952" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938952">(Feb 02 2021 at 21:25)</a>:</h4>
<p>same as <a href="https://github.com/rust-lang/rust/issues/70303">#70303</a>, right?</p>



<a name="224938958"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224938958" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224938958">(Feb 02 2021 at 21:25)</a>:</h4>
<p>sorry, i'm trying to go systematically here :)</p>



<a name="224939025"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939025" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939025">(Feb 02 2021 at 21:26)</a>:</h4>
<p>yes</p>



<a name="224939051"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939051" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939051">(Feb 02 2021 at 21:26)</a>:</h4>
<h1>GAT ICEs: different parameter counts, cat_expr Errd, broken MIR, debuginfo <a href="https://github.com/rust-lang/rust/issues/71176">#71176</a></h1>



<a name="224939083"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939083" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939083">(Feb 02 2021 at 21:26)</a>:</h4>
<p>This looks like it's probably fixed in the PR</p>



<a name="224939091"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939091" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939091">(Feb 02 2021 at 21:26)</a>:</h4>
<p>but blocking</p>



<a name="224939108"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939108" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939108">(Feb 02 2021 at 21:26)</a>:</h4>
<p>yes to both</p>



<a name="224939140"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939140" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939140">(Feb 02 2021 at 21:27)</a>:</h4>
<h1>Broken LLVM with GAT <a href="https://github.com/rust-lang/rust/issues/74684">#74684</a></h1>



<a name="224939172"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939172" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939172">(Feb 02 2021 at 21:27)</a>:</h4>
<p>Fixed by PR</p>



<a name="224939175"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939175" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939175">(Feb 02 2021 at 21:27)</a>:</h4>
<p>blocking</p>



<a name="224939272"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939272" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939272">(Feb 02 2021 at 21:28)</a>:</h4>
<p>known to be fixezd?</p>



<a name="224939274"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939274" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939274">(Feb 02 2021 at 21:28)</a>:</h4>
<p>ok</p>



<a name="224939327"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939327" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939327">(Feb 02 2021 at 21:28)</a>:</h4>
<p>yes</p>



<a name="224939335"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939335" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939335">(Feb 02 2021 at 21:28)</a>:</h4>
<p>(repro test case in PR)</p>



<a name="224939336"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939336" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939336">(Feb 02 2021 at 21:28)</a>:</h4>
<h1>Where clause in GAT must be repeated in function definition <a href="https://github.com/rust-lang/rust/issues/74798">#74798</a></h1>



<a name="224939374"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939374" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939374">(Feb 02 2021 at 21:28)</a>:</h4>
<p>looks like non-blocking</p>



<a name="224939390"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939390" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939390">(Feb 02 2021 at 21:29)</a>:</h4>
<p>hmm</p>



<a name="224939411"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939411" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939411">(Feb 02 2021 at 21:29)</a>:</h4>
<p>not GAT-specific</p>



<a name="224939435"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939435" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939435">(Feb 02 2021 at 21:29)</a>:</h4>
<p>this doesn't even look like it uses GATs</p>



<a name="224939460"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939460" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939460">(Feb 02 2021 at 21:29)</a>:</h4>
<p>am I missing something? :)</p>



<a name="224939489"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939489" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939489">(Feb 02 2021 at 21:29)</a>:</h4>
<p>heh, you're right</p>



<a name="224939576"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939576" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939576">(Feb 02 2021 at 21:30)</a>:</h4>
<p>woah</p>



<a name="224939608"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939608" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939608">(Feb 02 2021 at 21:30)</a>:</h4>
<p>so I think we can relabel this</p>



<a name="224939616"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939616" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939616">(Feb 02 2021 at 21:30)</a>:</h4>
<p>uh, wait</p>



<a name="224939641"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939641" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939641">(Feb 02 2021 at 21:30)</a>:</h4>
<div class="codehilite"><pre><span></span><code>error[E0658]: where clauses on associated types are unstable
  --&gt; src/lib.rs:19:5
   |
19 |     type ItemHolder: ItemHolder where &lt;Self::ItemHolder as ItemHolder&gt;::Item: Gen&lt;u32&gt;;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: see issue #44265 &lt;https://github.com/rust-lang/rust/issues/44265&gt; for more information
   = help: add `#![feature(generic_associated_types)]` to the crate attributes to enable
</code></pre></div>



<a name="224939652"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939652" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939652">(Feb 02 2021 at 21:31)</a>:</h4>
<p>ah, ok</p>



<a name="224939664"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939664" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939664">(Feb 02 2021 at 21:31)</a>:</h4>
<p>/me thinks</p>



<a name="224939709"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224939709" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224939709">(Feb 02 2021 at 21:31)</a>:</h4>
<p>I'm not convinced this where clause means what the issue filer thinks it means</p>



<a name="224940024"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940024" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940024">(Feb 02 2021 at 21:33)</a>:</h4>
<p>sorry, had to step away for a sec</p>



<a name="224940029"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940029" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940029">(Feb 02 2021 at 21:33)</a>:</h4>
<p>so--</p>



<a name="224940097"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940097" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940097">(Feb 02 2021 at 21:34)</a>:</h4>
<p>a where clause on an associated type, just like a where clause on a fn or whatever, means "you must prove this where clause is true to use the associated type"</p>



<a name="224940107"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940107" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940107">(Feb 02 2021 at 21:34)</a>:</h4>
<p>This is the same as <code>type ItemHolder: ItemHolder&lt;Item: Gen&lt;u32&gt;&gt;</code>, right?</p>



<a name="224940120"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940120" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940120">(Feb 02 2021 at 21:34)</a>:</h4>
<p>No</p>



<a name="224940139"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940139" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940139">(Feb 02 2021 at 21:34)</a>:</h4>
<p>it's subtle</p>



<a name="224940157"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940157" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940157">(Feb 02 2021 at 21:34)</a>:</h4>
<p>consider the distinction between</p>



<a name="224940175"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940175" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940175">(Feb 02 2021 at 21:35)</a>:</h4>
<p><code>type ItemHolder&lt;T: Ord&gt;: Eq</code></p>



<a name="224940209"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940209" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940209">(Feb 02 2021 at 21:35)</a>:</h4>
<p>let me make a table, our syntax is actually missing something like what this person wants</p>



<a name="224940340"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940340" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940340">(Feb 02 2021 at 21:36)</a>:</h4>
<p>A note on the subtlety here: we should probably think about strengthening the documentation and diagnostics are this at some point</p>



<a name="224940350"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940350" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940350">(Feb 02 2021 at 21:36)</a>:</h4>
<table>
<thead>
<tr>
<th>Syntax</th>
<th>who proves it</th>
<th>who can assume it</th>
</tr>
</thead>
<tbody>
<tr>
<td><code>type Foo: Bar = X</code></td>
<td>the impl</td>
<td>generic code using <code>T::Foo</code></td>
</tr>
<tr>
<td><code>type Foo&lt;A: Bar&gt; = X</code></td>
<td>generic code using <code>T::Foo&lt;U&gt;</code>, which must prove that <code>U: Bar</code></td>
<td>the impl, when proving the type <code>X</code> is WF</td>
</tr>
<tr>
<td><code>type Foo&lt;A&gt; = X where A: Bar</code></td>
<td>generic code using <code>T::Foo&lt;U&gt;</code>, which must prove that <code>U: Bar</code></td>
<td>the impl, when proving the type <code>X</code> is WF</td>
</tr>
</tbody>
</table>



<a name="224940353"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940353" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940353">(Feb 02 2021 at 21:36)</a>:</h4>
<p>(ah right, the <code>as ItemHolder</code> is creating the bound on that trait instead of the associated item)</p>



<a name="224940394"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940394" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940394">(Feb 02 2021 at 21:37)</a>:</h4>
<p>I can paste the above table and maybe close the issue, I think this is 'working as intended'</p>



<a name="224940465"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940465" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940465">(Feb 02 2021 at 21:37)</a>:</h4>
<p>I think that table doesn't quite make sense</p>



<a name="224940527"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940527" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940527">(Feb 02 2021 at 21:38)</a>:</h4>
<p>at least, naming of params could be better</p>



<a name="224940540"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940540" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940540">(Feb 02 2021 at 21:38)</a>:</h4>
<p>there is a typo</p>



<a name="224940551"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940551" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940551">(Feb 02 2021 at 21:38)</a>:</h4>
<p>for one thing :)</p>



<a name="224940599"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940599" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940599">(Feb 02 2021 at 21:38)</a>:</h4>
<p>is taht better?</p>



<a name="224940623"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940623" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940623">(Feb 02 2021 at 21:39)</a>:</h4>
<p>yes</p>



<a name="224940679"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940679" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940679">(Feb 02 2021 at 21:39)</a>:</h4>
<p>re. the issue, I think pasting table is good</p>



<a name="224940708"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940708" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940708">(Feb 02 2021 at 21:39)</a>:</h4>
<p>I will have to reread the code to be confident it's closable</p>



<a name="224940726"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940726" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940726">(Feb 02 2021 at 21:39)</a>:</h4>
<p>I closed it</p>



<a name="224940729"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940729" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940729">(Feb 02 2021 at 21:39)</a>:</h4>
<p>I'm all confidence :P</p>



<a name="224940803"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940803" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940803">(Feb 02 2021 at 21:40)</a>:</h4>
<p>I'm ok re-opening it though</p>



<a name="224940819"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940819" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940819">(Feb 02 2021 at 21:40)</a>:</h4>
<p>and we can close later if we still think that's true</p>



<a name="224940826"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940826" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940826">(Feb 02 2021 at 21:40)</a>:</h4>
<p>works for me</p>



<a name="224940930"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940930" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940930">(Feb 02 2021 at 21:41)</a>:</h4>
<h1>[nightly] ICE when using GATs with const generics <a href="https://github.com/rust-lang/rust/issues/75415">#75415</a></h1>



<a name="224940954"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940954" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940954">(Feb 02 2021 at 21:41)</a>:</h4>
<p>not blocking I think</p>



<a name="224940969"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224940969" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224940969">(Feb 02 2021 at 21:41)</a>:</h4>
<p>this seems entangled with the horror that is const generics parenting</p>



<a name="224941002"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941002" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941002">(Feb 02 2021 at 21:41)</a>:</h4>
<p>I'm going to see if this is the same with min_const_generics</p>



<a name="224941073"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941073" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941073">(Feb 02 2021 at 21:42)</a>:</h4>
<p>you could try enabling lazy norm -- <span class="user-mention" data-user-id="216206">@lcnr</span> what's the feature gate for that?</p>



<a name="224941089"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941089" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941089">(Feb 02 2021 at 21:42)</a>:</h4>
<p>But not blocing for lifetimes GATs</p>



<a name="224941094"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941094" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941094">(Feb 02 2021 at 21:42)</a>:</h4>
<p>I think that will change the way we do parent generics</p>



<a name="224941120"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941120" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941120">(Feb 02 2021 at 21:42)</a>:</h4>
<p>lazy norm is enabled for <code>const_generics</code></p>



<a name="224941145"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941145" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941145">(Feb 02 2021 at 21:42)</a>:</h4>
<p>but not for <code>min_const_generics</code></p>



<a name="224941199"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941199" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941199">(Feb 02 2021 at 21:43)</a>:</h4>
<p>so it's already enabled but still a problem?</p>



<a name="224941238"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941238" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941238">(Feb 02 2021 at 21:43)</a>:</h4>
<p>understood</p>



<a name="224941243"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941243" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941243">(Feb 02 2021 at 21:43)</a>:</h4>
<p>yes</p>



<a name="224941256"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941256" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941256">(Feb 02 2021 at 21:43)</a>:</h4>
<p>perhaps my diagnosis was wrong then</p>



<a name="224941267"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941267" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941267">(Feb 02 2021 at 21:43)</a>:</h4>
<p>though it's clearly connected somehow :)</p>



<a name="224941297"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941297" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941297">(Feb 02 2021 at 21:44)</a>:</h4>
<p>either way I'd call this more of a const generics bug</p>



<a name="224941339"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941339" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941339">(Feb 02 2021 at 21:44)</a>:</h4>
<p>but not sure</p>



<a name="224941364"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941364" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941364">(Feb 02 2021 at 21:44)</a>:</h4>
<p><span aria-label="shrug" class="emoji emoji-1f937" role="img" title="shrug">:shrug:</span>‍♀️</p>



<a name="224941401"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941401" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941401">(Feb 02 2021 at 21:44)</a>:</h4>
<h1>Bad GAT usage causes infinite build/check/run <a href="https://github.com/rust-lang/rust/issues/76187">#76187</a></h1>



<a name="224941425"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941425" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941425">(Feb 02 2021 at 21:44)</a>:</h4>
<p>(I'm happy with "not blocking" for <a href="https://github.com/rust-lang/rust/issues/75415">#75415</a> for now)</p>



<a name="224941457"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941457" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941457">(Feb 02 2021 at 21:45)</a>:</h4>
<p>so, this might be fixed by PR?</p>



<a name="224941462"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941462" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941462">(Feb 02 2021 at 21:45)</a>:</h4>
<p>maybe</p>



<a name="224941505"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941505" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941505">(Feb 02 2021 at 21:45)</a>:</h4>
<p>maybe not</p>



<a name="224941515"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941515" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941515">(Feb 02 2021 at 21:45)</a>:</h4>
<p>blocking though</p>



<a name="224941645"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941645" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941645">(Feb 02 2021 at 21:46)</a>:</h4>
<p>well</p>



<a name="224941656"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941656" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941656">(Feb 02 2021 at 21:46)</a>:</h4>
<p>seems blocking esque to me</p>



<a name="224941662"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941662" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941662">(Feb 02 2021 at 21:46)</a>:</h4>
<p>but I think what's happening here...</p>



<a name="224941717"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941717" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941717">(Feb 02 2021 at 21:47)</a>:</h4>
<p>it seems like the set of types reachable is infinite</p>



<a name="224941769"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941769" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941769">(Feb 02 2021 at 21:47)</a>:</h4>
<p>ah, hmm</p>



<a name="224941777"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941777" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941777">(Feb 02 2021 at 21:47)</a>:</h4>
<p>a bit hard for me to tell i guess</p>



<a name="224941780"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941780" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941780">(Feb 02 2021 at 21:47)</a>:</h4>
<p>I could be wrong</p>



<a name="224941814"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941814" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941814">(Feb 02 2021 at 21:47)</a>:</h4>
<p>this is wacky :)</p>



<a name="224941854"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941854" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941854">(Feb 02 2021 at 21:48)</a>:</h4>
<p>I would call this blocking</p>



<a name="224941869"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941869" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941869">(Feb 02 2021 at 21:48)</a>:</h4>
<p>Would this require some sort of cycle detection?</p>



<a name="224941873"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941873" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941873">(Feb 02 2021 at 21:48)</a>:</h4>
<p>yeah, I'm sure there's a more minimal repro here</p>



<a name="224941882"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941882" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941882">(Feb 02 2021 at 21:48)</a>:</h4>
<p>oh, sorry, you already said blocking</p>



<a name="224941893"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941893" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941893">(Feb 02 2021 at 21:48)</a>:</h4>
<p>I read your comment as 'non blocking'</p>



<a name="224941907"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941907" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941907">(Feb 02 2021 at 21:48)</a>:</h4>
<p>I guess I just agree then :)</p>



<a name="224941937"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224941937" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224941937">(Feb 02 2021 at 21:48)</a>:</h4>
<h1>Associated type constraint fails, even if it implements requested trait <a href="https://github.com/rust-lang/rust/issues/76407">#76407</a></h1>



<a name="224942026"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942026" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942026">(Feb 02 2021 at 21:49)</a>:</h4>
<p>I'm not sure</p>



<a name="224942039"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942039" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942039">(Feb 02 2021 at 21:49)</a>:</h4>
<p>probably blocking</p>



<a name="224942128"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942128" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942128">(Feb 02 2021 at 21:50)</a>:</h4>
<p>error: the trait bound <code>for&lt;'a&gt; &lt;MyStruct as MyTrait&gt;::Item&lt;'a&gt;: Marker</code> is not satisfied</p>



<a name="224942170"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942170" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942170">(Feb 02 2021 at 21:50)</a>:</h4>
<p>looks blocking</p>



<a name="224942183"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942183" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942183">(Feb 02 2021 at 21:50)</a>:</h4>
<p>looks fairly broken to me</p>



<a name="224942224"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942224" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942224">(Feb 02 2021 at 21:51)</a>:</h4>
<p>actually looks somewhat like just a regular associate type normalization issue</p>



<a name="224942226"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942226" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942226">(Feb 02 2021 at 21:51)</a>:</h4>
<p>probably a failed normalization</p>



<a name="224942243"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942243" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942243">(Feb 02 2021 at 21:51)</a>:</h4>
<p>yep</p>



<a name="224942265"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942265" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942265">(Feb 02 2021 at 21:51)</a>:</h4>
<p>kinda surprising</p>



<a name="224942307"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942307" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942307">(Feb 02 2021 at 21:51)</a>:</h4>
<p>I'm calling blocking, but might not be</p>



<a name="224942391"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942391" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942391">(Feb 02 2021 at 21:52)</a>:</h4>
<p><a href="https://play.rust-lang.org/?version=nightly&amp;mode=debug&amp;edition=2018&amp;gist=813908a74da25efecaba3204de2cb734">this variant fails to compile too</a></p>



<a name="224942400"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942400" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942400">(Feb 02 2021 at 21:52)</a>:</h4>
<p>that one doesn't use GATs</p>



<a name="224942404"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942404" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942404">(Feb 02 2021 at 21:52)</a>:</h4>
<p>probably the same bug</p>



<a name="224942449"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942449" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942449">(Feb 02 2021 at 21:53)</a>:</h4>
<p>I'm pretty sure I've seen this in a different issue</p>



<a name="224942463"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942463" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942463">(Feb 02 2021 at 21:53)</a>:</h4>
<p>I'm a bit torn on whether this is blocking</p>



<a name="224942469"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942469" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942469">(Feb 02 2021 at 21:53)</a>:</h4>
<p>I think probabl yes</p>



<a name="224942482"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942482" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942482">(Feb 02 2021 at 21:53)</a>:</h4>
<p>I think it's going to be a lot more common with GATs</p>



<a name="224942500"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942500" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942500">(Feb 02 2021 at 21:53)</a>:</h4>
<p>the code in the example looks pretty close to what I would call a "core GAT use case"</p>



<a name="224942511"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942511" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942511">(Feb 02 2021 at 21:53)</a>:</h4>
<p>I'm going to put down as blocking with playground link</p>



<a name="224942598"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942598" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942598">(Feb 02 2021 at 21:54)</a>:</h4>
<p>if you remove the GAT-ness, you just get</p>
<div class="codehilite" data-code-language="Rust"><pre><span></span><code><span class="k">fn</span> <span class="nf">ty_check</span><span class="o">&lt;</span><span class="n">T</span><span class="o">&gt;</span><span class="p">()</span><span class="w"></span>
<span class="k">where</span><span class="w"></span>
<span class="w">    </span><span class="n">T</span>: <span class="nc">MyTrait</span><span class="p">,</span><span class="w"></span>
<span class="w">    </span><span class="n">T</span>::<span class="n">Item</span>: <span class="nc">Marker</span><span class="w"></span>
<span class="p">{}</span><span class="w"></span>
</code></pre></div>



<a name="224942621"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942621" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942621">(Feb 02 2021 at 21:54)</a>:</h4>
<p>and it'd be pretty damn bad if that didn't work :)</p>



<a name="224942664"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942664" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942664">(Feb 02 2021 at 21:54)</a>:</h4>
<p>Running low on time, so let's try to get through rest</p>



<a name="224942675"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942675" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942675">(Feb 02 2021 at 21:54)</a>:</h4>
<p>I doubt we will</p>



<a name="224942684"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942684" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942684">(Feb 02 2021 at 21:54)</a>:</h4>
<p>probably not</p>



<a name="224942699"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942699" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942699">(Feb 02 2021 at 21:55)</a>:</h4>
<p>but i'm game to put in some more time later</p>



<a name="224942710"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942710" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942710">(Feb 02 2021 at 21:55)</a>:</h4>
<p>and/or read over log if you want to continue</p>



<a name="224942724"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942724" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942724">(Feb 02 2021 at 21:55)</a>:</h4>
<p>this seems very useful</p>



<a name="224942726"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942726" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942726">(Feb 02 2021 at 21:55)</a>:</h4>
<p>I can be around any time today</p>



<a name="224942752"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942752" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942752">(Feb 02 2021 at 21:55)</a>:</h4>
<h1>Compiler panics when creating a trait object for a trait which uses generic_associated_types <a href="https://github.com/rust-lang/rust/issues/76535">#76535</a></h1>



<a name="224942755"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942755" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942755">(Feb 02 2021 at 21:55)</a>:</h4>
<p>But I'll also probably just continue going through issues</p>



<a name="224942789"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942789" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942789">(Feb 02 2021 at 21:55)</a>:</h4>
<p>This might be fixed by PR</p>



<a name="224942803"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942803" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942803">(Feb 02 2021 at 21:56)</a>:</h4>
<p>"internal compiler error: impl item and trait item have different parameter counts"</p>



<a name="224942821"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942821" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942821">(Feb 02 2021 at 21:56)</a>:</h4>
<p>I thought maybe</p>



<a name="224942883"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942883" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942883">(Feb 02 2021 at 21:56)</a>:</h4>
<p>blocking either way</p>



<a name="224942887"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942887" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942887">(Feb 02 2021 at 21:56)</a>:</h4>
<p>blocking</p>



<a name="224942888"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942888" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942888">(Feb 02 2021 at 21:56)</a>:</h4>
<p>yes</p>



<a name="224942937"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942937" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942937">(Feb 02 2021 at 21:57)</a>:</h4>
<h1>ICE when combining GATs and HRTBs <a href="https://github.com/rust-lang/rust/issues/76826">#76826</a></h1>



<a name="224942971"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942971" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942971">(Feb 02 2021 at 21:57)</a>:</h4>
<p><span class="user-mention silent" data-user-id="232957">Jack Huey</span> <a href="#narrow/stream/144729-wg-traits/topic/meeting.202021-02-02/near/224942803">said</a>:</p>
<blockquote>
<p>"internal compiler error: impl item and trait item have different parameter counts"</p>
</blockquote>
<p>Oof it's actually changed now: "internal compiler error: compiler/rustc_middle/src/ty/subst.rs:476:25: Region parameter out of range when substituting in region 'a (index=1)"</p>



<a name="224942987"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224942987" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224942987">(Feb 02 2021 at 21:57)</a>:</h4>
<p>same gist I think</p>



<a name="224943073"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943073" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943073">(Feb 02 2021 at 21:58)</a>:</h4>
<p>this also might be fixed</p>



<a name="224943076"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943076" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943076">(Feb 02 2021 at 21:58)</a>:</h4>
<p>in PR</p>



<a name="224943088"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943088" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943088">(Feb 02 2021 at 21:58)</a>:</h4>
<p>I wondered</p>



<a name="224943121"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943121" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943121">(Feb 02 2021 at 21:58)</a>:</h4>
<p>I guess mark as blocking</p>



<a name="224943128"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943128" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943128">(Feb 02 2021 at 21:58)</a>:</h4>
<h1>GAT: unconstrained lifetime in output when using GAT in fn type <a href="https://github.com/rust-lang/rust/issues/77905">#77905</a></h1>



<a name="224943215"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943215" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943215">(Feb 02 2021 at 21:59)</a>:</h4>
<p>seems buggy</p>



<a name="224943238"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943238" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943238">(Feb 02 2021 at 21:59)</a>:</h4>
<p>the example seems buggy I mean</p>



<a name="224943242"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943242" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943242">(Feb 02 2021 at 21:59)</a>:</h4>
<p>something's weird</p>



<a name="224943244"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943244" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943244">(Feb 02 2021 at 21:59)</a>:</h4>
<p>gotta drop now!</p>



<a name="224943317"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943317" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943317">(Feb 02 2021 at 22:00)</a>:</h4>
<p>Yeah, I'm pretty sure I know where this is erroring out</p>



<a name="224943337"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943337" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943337">(Feb 02 2021 at 22:00)</a>:</h4>
<p>also worth checking if PR fixes</p>



<a name="224943382"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943382" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943382">(Feb 02 2021 at 22:00)</a>:</h4>
<p>since that will actually see the <code>'a</code> in the input</p>



<a name="224943411"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943411" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943411">(Feb 02 2021 at 22:00)</a>:</h4>
<p>blocking</p>



<a name="224943442"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943442" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943442">(Feb 02 2021 at 22:01)</a>:</h4>
<h1>GAT lifetime mismatch with type parametrised over dyn trait object with restricted lifetime <a href="https://github.com/rust-lang/rust/issues/78113">#78113</a></h1>



<a name="224943455"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943455" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943455">(Feb 02 2021 at 22:01)</a>:</h4>
<p><span class="user-mention silent" data-user-id="116009">nikomatsakis</span> <a href="#narrow/stream/144729-wg-traits/topic/meeting.202021-02-02/near/224941073">said</a>:</p>
<blockquote>
<p>you could try enabling lazy norm -- <span class="user-mention silent" data-user-id="216206">lcnr</span> what's the feature gate for that?</p>
</blockquote>
<p><a href="https://github.com/rust-lang/rust/issues/75415">#75415</a> is unrelated to lazy norm</p>



<a name="224943511"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943511" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943511">(Feb 02 2021 at 22:01)</a>:</h4>
<p>(the feature gate for that is either <code>const_generics</code> or <code>lazy_normalization_consts</code>)</p>



<a name="224943546"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943546" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943546">(Feb 02 2021 at 22:02)</a>:</h4>
<p>we have to get the right parent in <code>type_of</code>  and idk how that works</p>



<a name="224943595"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943595" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943595">(Feb 02 2021 at 22:02)</a>:</h4>
<p>but haven't looked too deeply into this myself yet</p>



<a name="224943661"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943661" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943661">(Feb 02 2021 at 22:02)</a>:</h4>
<p><span class="user-mention silent" data-user-id="232957">Jack Huey</span> <a href="#narrow/stream/144729-wg-traits/topic/meeting.202021-02-02/near/224943442">said</a>:</p>
<blockquote>
<h1>GAT lifetime mismatch with type parametrised over dyn trait object with restricted lifetime <a href="https://github.com/rust-lang/rust/issues/78113">#78113</a></h1>
</blockquote>
<p>This looks like potentially working as intended</p>



<a name="224943854"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943854" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943854">(Feb 02 2021 at 22:04)</a>:</h4>
<p>likely not blocking</p>



<a name="224943919"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224943919" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224943919">(Feb 02 2021 at 22:04)</a>:</h4>
<h1>ICE: compiler/rustc_middle/src/ty/subst.rs:529:17: type parameter <code>T/#1</code> (T/1) out of range when substituting, substs=Self <a href="https://github.com/rust-lang/rust/issues/78671">#78671</a></h1>



<a name="224944008"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944008" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944008">(Feb 02 2021 at 22:05)</a>:</h4>
<p>example isn't quite enough</p>



<a name="224944068"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944068" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944068">(Feb 02 2021 at 22:06)</a>:</h4>
<p>weird example yeah</p>



<a name="224944128"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944128" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944128">(Feb 02 2021 at 22:06)</a>:</h4>
<p>comments have a better repro</p>



<a name="224944178"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944178" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944178">(Feb 02 2021 at 22:07)</a>:</h4>
<p>still a weird example</p>



<a name="224944191"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944191" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944191">(Feb 02 2021 at 22:07)</a>:</h4>
<p>Wait, regression-from-stable-to-stable?</p>



<a name="224944196"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944196" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944196">(Feb 02 2021 at 22:07)</a>:</h4>
<p>On a GAT issue?</p>



<a name="224944224"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944224" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944224">(Feb 02 2021 at 22:07)</a>:</h4>
<p><span aria-label="shrug" class="emoji emoji-1f937" role="img" title="shrug">:shrug:</span>‍♀️</p>



<a name="224944287"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944287" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944287">(Feb 02 2021 at 22:08)</a>:</h4>
<p>I'm going to put as non-blocking, since it's a type GAT</p>



<a name="224944289"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944289" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944289">(Feb 02 2021 at 22:08)</a>:</h4>
<p>doesn't feel blocking</p>



<a name="224944300"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944300" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944300">(Feb 02 2021 at 22:08)</a>:</h4>
<p>and the example is really weird</p>



<a name="224944326"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944326" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944326">(Feb 02 2021 at 22:08)</a>:</h4>
<p>It wouldn't be valid code if everything worked correctly</p>



<a name="224944377"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944377" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944377">(Feb 02 2021 at 22:09)</a>:</h4>
<h1><code>generic_associated_types</code> fails on dyn dyn  <a href="https://github.com/rust-lang/rust/issues/79422">#79422</a></h1>



<a name="224944403"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944403" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944403">(Feb 02 2021 at 22:09)</a>:</h4>
<p>blocking, possibly fixed by PR</p>



<a name="224944413"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944413" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944413">(Feb 02 2021 at 22:09)</a>:</h4>
<p>yup</p>



<a name="224944515"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944515" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944515">(Feb 02 2021 at 22:10)</a>:</h4>
<h1>Compiler panic during GAT type bound usage <a href="https://github.com/rust-lang/rust/issues/79636">#79636</a></h1>



<a name="224944526"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944526" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944526">(Feb 02 2021 at 22:10)</a>:</h4>
<p>oh joy, a Monad example</p>



<a name="224944554"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944554" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944554">(Feb 02 2021 at 22:11)</a>:</h4>
<p>non blocking</p>



<a name="224944566"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944566" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944566">(Feb 02 2021 at 22:11)</a>:</h4>
<p>type GAT, possibly fixed by PR</p>



<a name="224944685"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944685" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944685">(Feb 02 2021 at 22:12)</a>:</h4>
<p>Definitely should work on diagnostics here though</p>



<a name="224944700"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944700" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944700">(Feb 02 2021 at 22:12)</a>:</h4>
<p>(I imagine we can get the same thing with lifetimes)</p>



<a name="224944715"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944715" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944715">(Feb 02 2021 at 22:12)</a>:</h4>
<p>Is it safe to assume that such ICEs are not a problem with lifetimes only?</p>



<a name="224944727"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944727" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944727">(Feb 02 2021 at 22:12)</a>:</h4>
<p>seems valid in this case at least, just checked</p>



<a name="224944782"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944782" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944782">(Feb 02 2021 at 22:13)</a>:</h4>
<p>ah nvm, it mentions substituting type params</p>



<a name="224944846"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944846" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944846">(Feb 02 2021 at 22:13)</a>:</h4>
<p>yeah, seems like a type-only thing</p>



<a name="224944858"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944858" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944858">(Feb 02 2021 at 22:13)</a>:</h4>
<p><em>but</em></p>



<a name="224944932"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944932" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944932">(Feb 02 2021 at 22:14)</a>:</h4>
<p>the same underlying problem - not specific vars on GAT - could happen with lifetimes</p>



<a name="224944959"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944959" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944959">(Feb 02 2021 at 22:14)</a>:</h4>
<h1>ICE with const generics and GATs <a href="https://github.com/rust-lang/rust/issues/79666">#79666</a></h1>



<a name="224944984"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944984" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944984">(Feb 02 2021 at 22:14)</a>:</h4>
<p>another const parent path ICE</p>



<a name="224944995"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224944995" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224944995">(Feb 02 2021 at 22:14)</a>:</h4>
<p>non-blocking, const GAT</p>



<a name="224945048"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224945048" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224945048">(Feb 02 2021 at 22:15)</a>:</h4>
<h1><a href="https://github.com/rust-lang/rust/issues/79768">#79768</a> - Internal Compiler Error caused by Generic Associated Types</h1>



<a name="224945191"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224945191" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224945191">(Feb 02 2021 at 22:16)</a>:</h4>
<p>non-blocking, type GAT</p>



<a name="224945283"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224945283" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224945283">(Feb 02 2021 at 22:16)</a>:</h4>
<p>looks similar to <a href="https://github.com/rust-lang/rust/issues/79636">#79636</a></p>



<a name="224945445"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224945445" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224945445">(Feb 02 2021 at 22:17)</a>:</h4>
<h1><a href="https://github.com/rust-lang/rust/issues/80433">#80433</a> - ICE when using "Generic Associated Types" feature with references for impl block</h1>



<a name="224945491"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224945491" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224945491">(Feb 02 2021 at 22:17)</a>:</h4>
<p>also fixed by 79554</p>



<a name="224945550"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224945550" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224945550">(Feb 02 2021 at 22:18)</a>:</h4>
<p>Possibly</p>



<a name="224945570"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224945570" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224945570">(Feb 02 2021 at 22:18)</a>:</h4>
<p>hm, or does it need a workaround?</p>



<a name="224945571"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224945571" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224945571">(Feb 02 2021 at 22:18)</a>:</h4>
<p>blocking</p>



<a name="224945626"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224945626" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224945626">(Feb 02 2021 at 22:18)</a>:</h4>
<p>3 more</p>



<a name="224945630"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224945630" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224945630">(Feb 02 2021 at 22:18)</a>:</h4>
<h1><a href="https://github.com/rust-lang/rust/issues/80626">#80626</a> - Enum variant with GAT field fails to derive Sized</h1>



<a name="224945655"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224945655" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224945655">(Feb 02 2021 at 22:19)</a>:</h4>
<p>non-blocking, type GAT</p>



<a name="224945819"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224945819" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224945819">(Feb 02 2021 at 22:20)</a>:</h4>
<p>this is a bit weird though</p>



<a name="224945823"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224945823" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224945823">(Feb 02 2021 at 22:20)</a>:</h4>
<p>oh wait, no</p>



<a name="224945860"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224945860" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224945860">(Feb 02 2021 at 22:21)</a>:</h4>
<p>Because when variants have more than 1 field, all but last field must be <code>Sized</code></p>



<a name="224945877"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224945877" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224945877">(Feb 02 2021 at 22:21)</a>:</h4>
<p>err wait</p>



<a name="224945901"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224945901" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224945901">(Feb 02 2021 at 22:21)</a>:</h4>
<p>it it recursive?</p>



<a name="224945918"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224945918" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224945918">(Feb 02 2021 at 22:22)</a>:</h4>
<p>that's backwards from what I expect</p>



<a name="224945988"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224945988" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224945988">(Feb 02 2021 at 22:22)</a>:</h4>
<p>yes, it's recursive</p>



<a name="224946015"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224946015" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224946015">(Feb 02 2021 at 22:23)</a>:</h4>
<p>So, the last field being sized is checked when proving the <code>Struct: Sized</code> bound, while the other fields are only checked when checking the item is well-formed.</p>



<a name="224946047"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224946047" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224946047">(Feb 02 2021 at 22:23)</a>:</h4>
<p>Thanks <span class="user-mention" data-user-id="116118">@Matthew Jasper</span></p>



<a name="224946083"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224946083" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224946083">(Feb 02 2021 at 22:24)</a>:</h4>
<p>Ah right</p>



<a name="224946169"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224946169" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224946169">(Feb 02 2021 at 22:24)</a>:</h4>
<p><a href="https://play.rust-lang.org/?version=nightly&amp;mode=debug&amp;edition=2018&amp;gist=f83e644bf061ffcb1e9fddd14f5dbd41">https://play.rust-lang.org/?version=nightly&amp;mode=debug&amp;edition=2018&amp;gist=f83e644bf061ffcb1e9fddd14f5dbd41</a> works, so specific to type GATs</p>



<a name="224946176"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224946176" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224946176">(Feb 02 2021 at 22:24)</a>:</h4>
<p>definitely non blocking</p>



<a name="224946204"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224946204" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224946204">(Feb 02 2021 at 22:24)</a>:</h4>
<h1><a href="https://github.com/rust-lang/rust/issues/80982">#80982</a> - Error in trait solving</h1>



<a name="224946249"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224946249" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224946249">(Feb 02 2021 at 22:25)</a>:</h4>
<p>Related to 78113, which was likely not blocking</p>



<a name="224946357"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224946357" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224946357">(Feb 02 2021 at 22:26)</a>:</h4>
<p>right</p>



<a name="224946360"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224946360" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224946360">(Feb 02 2021 at 22:26)</a>:</h4>
<p>I think same</p>



<a name="224946396"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224946396" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224946396">(Feb 02 2021 at 22:26)</a>:</h4>
<p>but this is a little more complicated</p>



<a name="224946493"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224946493" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224946493">(Feb 02 2021 at 22:27)</a>:</h4>
<p>specifically, the question is does <code>impl&lt;'a&gt; A for &amp;'a Box&lt;dyn A + 'a&gt;</code> satisfy <code>T&lt;'a&gt; : A</code> where the impl is <code>T&lt;'a&gt; = &amp;'a Box&lt;dyn A + 'a&gt;</code></p>



<a name="224946601"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224946601" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224946601">(Feb 02 2021 at 22:28)</a>:</h4>
<p>I <em>think</em> this is working as intended</p>



<a name="224946673"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224946673" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224946673">(Feb 02 2021 at 22:29)</a>:</h4>
<p>We definitely need better diagnostics then, to avoid getting more of these bug reports</p>



<a name="224946762"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224946762" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224946762">(Feb 02 2021 at 22:30)</a>:</h4>
<p>yeah, dianostics here are bad</p>



<a name="224946793"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224946793" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224946793">(Feb 02 2021 at 22:30)</a>:</h4>
<p>essentially trying to coerce <code>Foo</code> to <code>dyn A + 'a</code></p>



<a name="224946836"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224946836" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224946836">(Feb 02 2021 at 22:30)</a>:</h4>
<p>likely not blocking</p>



<a name="224946839"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224946839" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224946839">(Feb 02 2021 at 22:30)</a>:</h4>
<p>yeah, the last part of expected/found makes sense</p>



<a name="224946865"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224946865" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224946865">(Feb 02 2021 at 22:31)</a>:</h4>
<div class="codehilite"><pre><span></span><code>   = note: expected reference `&amp;&#39;a Box&lt;(dyn A + &#39;a)&gt;`
              found reference `&amp;&#39;a Box&lt;Foo&gt;`
</code></pre></div>



<a name="224946891"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224946891" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224946891">(Feb 02 2021 at 22:31)</a>:</h4>
<p>That message is essentially correct,</p>



<a name="224946930"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224946930" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224946930">(Feb 02 2021 at 22:31)</a>:</h4>
<p>There's no unsizing coercion for two layers of pointers.</p>



<a name="224947019"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947019" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947019">(Feb 02 2021 at 22:32)</a>:</h4>
<p>I'm actually going to move it to not blocking</p>



<a name="224947036"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947036" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947036">(Feb 02 2021 at 22:32)</a>:</h4>
<p>But it's not closable because diagnostics</p>



<a name="224947046"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947046" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947046">(Feb 02 2021 at 22:32)</a>:</h4>
<h1><a href="https://github.com/rust-lang/rust/issues/81487">#81487</a> - Error when inferring a lifetime in return type using GATs</h1>



<a name="224947047"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947047" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947047">(Feb 02 2021 at 22:32)</a>:</h4>
<p>Not blocking and not a GAT issue</p>



<a name="224947089"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947089" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947089">(Feb 02 2021 at 22:33)</a>:</h4>
<p>last one <span aria-label="tada" class="emoji emoji-1f389" role="img" title="tada">:tada:</span></p>



<a name="224947209"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947209" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947209">(Feb 02 2021 at 22:34)</a>:</h4>
<p>that's a lot of reference layers</p>



<a name="224947248"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947248" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947248">(Feb 02 2021 at 22:34)</a>:</h4>
<p>yeah</p>



<a name="224947274"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947274" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947274">(Feb 02 2021 at 22:35)</a>:</h4>
<p>this looks...like it should work</p>



<a name="224947281"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947281" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947281">(Feb 02 2021 at 22:35)</a>:</h4>
<p>That one (<a href="https://github.com/rust-lang/rust/issues/81487">#81487</a>) is blocking</p>



<a name="224947309"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947309" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947309">(Feb 02 2021 at 22:35)</a>:</h4>
<p>it does? huh, my intuition is wrong then</p>



<a name="224947365"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947365" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947365">(Feb 02 2021 at 22:35)</a>:</h4>
<p>yeah, basically see that <code>RefWrapper(the_ref)</code> replaced with <code>RefWrapper::&lt;'a, T&gt;(the_ref)</code> works</p>



<a name="224947366"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947366" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947366">(Feb 02 2021 at 22:35)</a>:</h4>
<p>It works with <code>feature(nll)</code></p>



<a name="224947448"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947448" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947448">(Feb 02 2021 at 22:36)</a>:</h4>
<p>So, maybe I should finish my attempts to stabilize that.</p>



<a name="224947464"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947464" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947464">(Feb 02 2021 at 22:36)</a>:</h4>
<p>What exactly does that feature enable?</p>



<a name="224947484"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947484" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947484">(Feb 02 2021 at 22:37)</a>:</h4>
<p>It disables region checking in (HIR) typeck</p>



<a name="224947507"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947507" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947507">(Feb 02 2021 at 22:37)</a>:</h4>
<p>interesting</p>



<a name="224947535"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947535" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947535">(Feb 02 2021 at 22:37)</a>:</h4>
<p>that's very non-obvious when looking at the errors</p>



<a name="224947593"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947593" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947593">(Feb 02 2021 at 22:38)</a>:</h4>
<p>Yeah. I think with potentially better diagnostics it's okay</p>



<a name="224947599"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947599" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947599">(Feb 02 2021 at 22:38)</a>:</h4>
<p>but as-is, blocking</p>



<a name="224947609"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947609" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947609">(Feb 02 2021 at 22:38)</a>:</h4>
<p>anyways, that's all the issues</p>



<a name="224947613"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947613" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947613">(Feb 02 2021 at 22:38)</a>:</h4>
<p>I gotta run</p>



<a name="224947826"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947826" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947826">(Feb 02 2021 at 22:40)</a>:</h4>
<p>In conclusion, we should probably review again after <a href="https://github.com/rust-lang/rust/issues/79554">#79554</a> lands</p>



<a name="224947931"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/224947931" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#224947931">(Feb 02 2021 at 22:41)</a>:</h4>
<p>Only about 5 issues besides that, assuming the others are all fixed by that</p>



<a name="225335992"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/meeting%202021-02-02/near/225335992" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/meeting.202021-02-02.html#225335992">(Feb 05 2021 at 18:17)</a>:</h4>
<p>Trait objects are in a weird place where they don't work (at least if you try to call any methods), but we don't error until the trait system.</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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